An international team of scientists led by English geologist Tim Wright from the University of Leeds is studying the seismic events taking place in the Afar region of Ethiopia—also called the Denakil Depression—which is also located in the Red Sea-coastal countries of Djibouti and Eritrea. The Denakil Depression—located south of the Denakil Alps, which separates the Denakil Desert from the Red Sea—is a large triangular basin that descends to a depth of about 390 feet (120 meters) below sea level.

Scientists from England, United States, New Zealand, France, and Ethiopia are using satellite and ground technologies such as the Global Positioning System (GPS) and seismometers to analyze and record movements of rock, magma, and crust during this very exciting time of geological history for the Earth.

Continental drift is a hypothesis first proposed in the early 1900s stating that the Earth’s continents are moving relative to each other. Scientists noted that the shape of the continents seem to fit together. Some scientists specifically noted that the shapes of Africa and South America on the Atlantic Ocean sides seem to fit together—implying that in the very distant past they may have been physically together. In the 1960s, the hypothesis of continental drift and the concept of seafloor spreading were merged into the geological theory of plate tectonics.

Plate tectonics involves the outermost two layers of the Earth’s interior. The first layer—the lithosphere—is the solid uppermost shell of the Earth, which is between 0 to 100 kilometers below the Earth’s surface. It is composed of the crust and the upper part of the mantle. The lithosphere is the layer containing the tectonic plates. Thus, the movement of the lithospheric plates is called plate tectonics.

The second layer—the asthenosphere—is between 100 and 300 kilometers below the Earth’s surface. It flows very slowly, and is weaker and hotter than the lithosphere layer above it. The lithosphere rides on the asthenosphere. Historically, the lithospheric plates (or tectonic plates) move at a rate of about 14 to 17 millimeters per year. Today, they can move up to 185 millimeters in any given year.

The Earth has seven major tectonic plates (Pacific, Eurasian, African, North American, Antarctic, South American, and Indo-Australian) and numerous minor ones (such as Indian, Arabian, Caribbean, Juan de Fuca, and Nazca). Scientists frequently find earthquakes, ocean trenches, mountains, and volcanoes along tectonic plate boundaries.

Dr. Wright commented on the Denakil discovery, “It’s very exciting because we’re witnessing the birth of a new ocean. In geological terms, a million years is the blink of an eye. We don’t precisely know what is going to happen, but we believe that it may turn parts of Northern Ethiopia and Eritrea into an island, before a much larger land mass—the horn of Africa—breaks off from the continent.”

Histories of plate tectonics appear at: http://www.ucmp.berkeley.edu/geology/tectonics.html and http://pubs.usgs.gov/gip/dynamic/understanding.html.

{moscomment}